Slit valve having increased flow uniformity

ABSTRACT

Methods and apparatus for increasing flow uniformity are provided herein. In some embodiments, a slit valve having increased flow uniformity may be provided, the slit valve may include a housing having an opening disposed therethrough, the opening configured to allow a substrate to pass therethrough; a gas inlet formed in the housing; an outer plenum disposed in the housing and coupled to the gas inlet; an inner plenum disposed in the housing and coupled to the outer plenum via a plurality of holes; and a plurality of gas outlets disposed in the housing and fluidly coupling the opening to the inner plenum.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention generally relate to semiconductorprocessing.

2. Description of the Related Art

As the demand for semiconductor devices continues to grow, there is aconstant need to increase manufacturing throughput without sacrificingdevice quality. Some methods include an apparatus for treating, and/orcleaning the semiconductor wafer as it is passed into a vacuum transferchamber and/or a semiconductor process chamber. Such methods includepassing the wafer through a curtain of a process gas or gases as it istransferred into a semiconductor process chamber. These methods canreduce the processing time for manufacturing a semiconductor device.

However, conventional apparatus used to perform these methods do notuniformly treat and/or clean the surface of the substrate. This uneventreatment, and/or cleaning of the substrate surface can result in poorlyfabricated semiconductor devices that may not function properly.

Thus, there is a need for an improved apparatus for treating, and/orcleaning the surface of semiconductor substrates more uniformly.

SUMMARY

Methods and apparatus for increasing flow uniformity are providedherein. In some embodiments, a slit valve having increased flowuniformity may be provided, the slit valve may include a housing havingan opening disposed therethrough, the opening configured to allow asubstrate to pass therethrough; a gas inlet formed in the housing; anouter plenum disposed in the housing and coupled to the gas inlet; aninner plenum disposed in the housing and coupled to the outer plenum viaa plurality of holes; and a plurality of gas outlets disposed in thehousing and fluidly coupling the opening to the inner plenum.

In some embodiments, a slit valve may include a housing having anopening disposed therethrough, the opening configured to allow asubstrate to pass therethrough; a gas inlet formed in the housing; aplenum disposed in the housing and coupled to the gas inlet; a pluralityof gas outlets disposed in the housing and fluidly coupling the openingto the plenum; and a counterbore disposed on a plenum side of one ormore of the gas outlets.

In some embodiments, an apparatus for processing a substrate may includea process chamber; and a slit valve coupled to the process chamber, theslit valve including a housing having an opening disposed therethrough,the opening configured to allow a substrate to pass therethrough; a gasinlet formed in the housing; an outer plenum disposed in the housing andcoupled to the gas inlet; an inner plenum disposed in the housing andcoupled to the outer plenum via a plurality of holes; and a plurality ofgas outlets disposed in the housing and fluidly coupling the opening tothe inner plenum.

In some embodiments, an apparatus for processing a substrate may includea process chamber; and a slit valve coupled to the process chamber, theslit valve including a housing having an opening disposed therethrough,the opening configured to allow a substrate to pass therethrough; a gasinlet formed in the housing; a plenum disposed in the housing andcoupled to the gas inlet; a plurality of gas outlets disposed in thehousing and fluidly coupling the opening to the plenum; and acounterbore disposed on a plenum side of one or more of the gas outlets.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 illustrates an apparatus in accordance with some embodiments ofthe present invention.

FIGS. 2A-C illustrate a cross sectional view of a slit valve inaccordance with some embodiments of the present invention.

FIG. 3A-B illustrate a cross sectional view of a slit valve inaccordance with some embodiments of the present invention.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. The figures are not drawn to scale and may be simplifiedfor clarity. It is contemplated that elements and features of oneembodiment may be beneficially incorporated in other embodiments withoutfurther recitation.

DETAILED DESCRIPTION

Embodiments of the present invention provide methods and apparatus forproviding more uniform gas distribution and/or flow through an opening.In some embodiments, a slit valve suitable for treating a substrate asthe substrate is transferred into a process chamber via a slit valveopening is provided. In some embodiments, the slit valves mayadvantageously be configured to more uniformly impinge one or more gasesupon a surface of a substrate passing through the slit valve opening.

Embodiments of slit valves in accordance with the present invention maybe utilized in any process chamber where it is desired to treat asubstrate as it passes into or out of the process chamber. For example,suitable process chambers may include semiconductor substrate processchambers, vacuum processing chambers, thermal processing chambers,plasma processing chambers, annealing chambers, or the like. Examples ofsuitable chambers include the CENTURA chamber, and the RP EPI chamber,respectively, as well as other chambers, all available from AppliedMaterials, Inc. of Santa Clara, Calif. Other chambers may also suitablyuse the inventive slit valves.

As a non-limiting, illustrative example, FIG. 1 illustrates a processchamber 100 coupled to a transfer chamber 116 via a slit valve 112 inaccordance with some embodiments of the present invention. The processchamber 100 may be any suitable process chamber, as discussed above. Anexemplary process chamber 100 may include an inner volume 104 having asubstrate support pedestal 106 disposed therein for supporting asubstrate 102 thereupon. Optionally, the process chamber 100 may includevarious other components (not shown) suitable for the particular processto be performed within the process chamber 100, such as one or more agas inlets for delivering a process gas or gases to the inner volume104, plasma generating apparatus, heating apparatus (such as lasers,heat lamps, resistive heaters, or the like), pumping apparatus forgenerating and maintaining a desired pressure within the process chamber100, and the like.

The process chamber 100 may further include an opening 108 sized tofacilitate passing the substrate 102 therethrough by a substratetransfer device 110 during operation. The transfer device 110 mayinclude a substrate transfer robot such as those commonly found in loadlock chambers and vacuum transfer chambers.

The transfer chamber 116 may be a vacuum transfer chamber, a load lockchamber, a factory interface, or any other suitable chamber useful fortransferring a substrate to or from the process chamber 100.Alternatively, in some embodiments, the transfer chamber 116 may beomitted.

The slit valve may be disposed between the process chamber 100 and thetransfer chamber 116 proximate the opening 108 in the process chamber100. The slit valve 112 has a slit valve opening 120 generallyconfigured to align with the opening 108 and facilitate passing thesubstrate 102 between the process chamber 100 and the transfer chamber116. A door 114 may be provided to selectively open and close the slitvalve 112 and thereby provide access to or isolate the inner volume 104of the process chamber 100, for example, to place a substrate 102 on thepedestal 106.

The slit valve 112 may be coupled to a gas source 118 for providing oneor more gases for treating the substrate 102 as it passes through theslit valve opening 120 during operation. The one or more gases may beany suitable gas or gases for treating the substrate as desired in aparticular application.

In some embodiments, the slit valve may include an inlet for coupling tothe gas source 118 and a plurality of outlets distributed across theslit valve opening 120 in a configuration designed to provide a uniformgas flow. One or more plenums may be provided between the inlet and theplurality of outlets to facilitate control over the flow of the gas(es)out of the plurality of outlets. In some embodiments, the geometry ofthe one or more plenums may be configured to control the flow of thegas(es) as desired. In some embodiments, the geometry of the pluralityof outlets may be configured to control the flow of the gas(es) asdesired.

For example, a cross sectional view of a slit valve in accordance withsome embodiments of the present invention is illustrated in FIGS. 2A-C.As shown in FIG. 2A, the slit valve may include a housing 202 having anopening 120 disposed therethrough. A gas inlet 206 may be provided inthe housing 202 for coupling the slit valve to a gas source (such as gassource 118 shown in FIG. 1). The gas inlet 206 may be fluidly coupled toa first plenum 212 in the housing 202. A second plenum 214 in thehousing 202 is coupled to the first plenum 212 via a plurality of holes210. A plurality of gas outlets 204 may be provided for coupling thesecond plenum 214 to the opening 120. The plurality of gas outlets 204are arranged to provide a flow of gas to a surface of a substratepassing through the opening 120.

In some embodiments, the first plenum 212 and the second plenum 214 maybe at least partially defined within the housing 202 by an insert 208configured to fit at least partially within a recess 216 in the housing202. The insert 208 may include a base 218 having walls 220 protrudingtherefrom. The walls 220 may be configured to engage a lower surface ofthe recess 216 to define the two plenums 212, 214 (e.g., the outerplenum 212 is defined between the walls 220 and the wall of the housing202 bounding the recess 216, and the inner plenum 214 is defined withinthe walls 220 of the insert 208). In some embodiments, and as best shownin FIG. 2B, the outer plenum 212 may circumscribe the inner plenum 214.

The walls 220 may have the plurality of openings 210 contained thereinto fluidly couple the outer and inner plenums 212, 214. The number,geometry, and arrangement of the plurality of holes 210 may becontrolled as desired to control the flow of gas from the outer plenum212 to the inner plenum 214. For example, in some embodiments, the holes210 may be substantially equidistantly spaced from each other along eachside of a wall separating the outer and inner plenums 212, 214 (e.g.,the wall 220) to facilitate even distribution of gas pressure in theouter plenum. In some embodiments at least 2 holes 210 may be provided,or in some embodiments, up to about 50 holes 210 may be provided. Thenumber of holes provided will vary depending upon the volume of theplenums, the desired flow requirements, and the like. As such, othernumbers of holes may be utilized as needed for a particular application.The diameter of the holes 210 (or open area) may be defined tofacilitate control over the rate of gas flow from the outer plenum 212to the inner plenum 214. In some embodiments, the holes 210 may have adiameter of between about 0.01 inch to about 0.1 inches. It iscontemplated that other diameters may be used in other applicationshaving different plenum volumes or flow requirements.

The plurality of gas outlets 204 may be disposed within the areadefining inner plenum 214. The number, geometry, total open area, andlike characteristics of the gas outlets 204 may be selected as desiredto facilitate control over the exit velocity of the gas flowing out ofthe inner plenum 214 and into the opening 120. In some embodiments, thegas outlets 204 may be offset from the location of the plurality ofholes 210, thereby facilitating equalization of pressure and gas flowwithin the inner plenum 214. In some embodiments, the slit valve mayinclude up to about 40 gas outlets 204. The gas outlets may be arrangedin a single line, in multiple lines, or in any other two dimensionalarrangement. The two dimensional arrangement may comprise of uniformlyor non-uniformly spaced rows, aligned or staggered rows, or any randomdistribution of gas outlets. In some embodiments, between about 20 toabout 40 gas outlets 204 may be arranged in a single line. In someembodiments, about 20 gas outlets 204 may be arranged in a single line.

In operation, a flow of one or more gases may be provided to the outerplenum 212 via the gas inlet 206. Due to the relatively small size ofthe holes 210, the gas will tend to fill and pressurize the outer plenum212 prior to substantially entering the inner plenum 214. Thus, the gaspressure within the outer plenum 212 will be substantially even aboutthe inner plenum 214. As such, the gas flowing into the inner plenum 214through the holes 210 will also be entering at a relatively uniform, oreven, rate, and the pressure within the inner plenum 214 will besubstantially uniform. The gas provided to the slit valve will then flowout of the inner plenum 214 and into the opening 120 via the gas outlets204. As the pressure within the inner plenum 214 is more uniform than ifonly a single plenum were provided with a single gas inlet, the exitvelocity of the gas flowing out of the gas outlets 204 will be moreuniform than in conventional apparatus. Thus, the arrangement of thefirst plenum 212 and the second plenum 214 may advantageously equalizethe gas pressure proximate the plurality of gas outlets 204 tofacilitate more uniform gas flow therethrough during operation. In someembodiments, the flow rate of gas exiting each gas outlet 204 may becontrolled to be uniform to greater than about 70 percent, or in someembodiments, greater than about 80 percent, or in some embodiments,greater than about 90 percent, or in some embodiments, between about 90to about 97 percent.

The slit valve described above with respect to FIGS. 2A-C is exemplaryonly, and other slit valves in accordance with the present invention arecontemplated. For example, FIGS. 3A-B illustrate a cross-sectional viewof a slit valve in accordance with some embodiments of the presentinvention. The slit valve includes a housing 302 having an opening 120disposed therethrough. A plenum 310 is at least partially disposedwithin the housing 302. A gas inlet 306 may be disposed in the housing302 for coupling the plenum 310 to a gas source (such as gas source 118depicted in FIG. 1). A plurality of gas outlets 304 may be disposed inthe housing for coupling the plenum 310 to the opening 120. In someembodiments, at least some of the plurality of gas outlets 304 mayfurther include a counterbore 318 disposed proximate the plenum 310. Forexample, as shown in FIG. 3, each gas outlet 304 may have a counterbore318 formed on the plenum-side of the outlet 304.

As discussed above with respect to FIGS. 2A-C, the number, size, andgeometry of the plurality of gas outlets 304 (and the counterbores 318)may be controlled as desired to facilitate control over the exitvelocity of the gas flowing into the opening 120. For example, in someembodiments, the slit valve may include about 20 gas outlets 304, or insome embodiments about 78 gas outlets 304, or in some embodiments about96 gas outlets 304. In some embodiments, about 20 gas outlets may beprovided in a single line. Alternatively, in some embodiments, about 78or about 96 gas outlets may be provided in two rows, each row havingabout half of the total gas outlets.

While the embodiment depicted in FIGS. 3A-B shows counterbores 318 andgas outlets 304 that are circular, any such shapes which may facilitatea more uniform gas flow through the plurality of gas outlets 304 duringoperation may be used.

In some embodiments, the plenum 310 may be at least partially defined bya recess 312 of the housing 302. For example, in some embodiments, acover, or plate 308 may be provided atop the recess to define the plenum310.

The slit valve may be configured to provide one or more design featuresthat urge the flow of the gas delivered to the plenum 310 to bedistributed as desired (e.g., to provide a more uniform flow of the gasto the opening 120). For example, in some embodiments, the plenum 310may have a volume that varies along a longitudinal length thereof. Forexample, the volume may increase along the longitudinal length of theplenum in a direction moving away from the gas inlet 306. In someembodiments, the volume of the plenum 310 may be controlled by providingthe recess 312 with an inclined bottom surface (although any othersuitable method may be utilized as well). The rate of change of thevolume may be controlled as desired to facilitate moving the gasdelivered to the plenum 310 along the length of the plenum 310 (e.g.,towards the larger volume). For example, in some embodiments the bottomsurface of the recess 312 may be inclined at a downward angle (away fromthe gas inlet 306) of up to about 10 degrees, or in some embodiments,about 5 degrees. It is believed that the larger volume facilitatesproviding a “path of least resistance” that helps reduce the exitvelocity of the gas from gas outlets 304 proximate the gas inlet 306,thereby making the exit flow across the opening 120 more uniform ascompared to conventional configurations.

Alternatively or in combination with the foregoing, in some embodiments,a volume of at least one counterbore 318 may be different than a volumeof at least one other counterbore 318. In some embodiments, the volumeof each counterbore 318 may vary along a distance proximate from the gasinlet 306. In some embodiments, the volume of each counterbore 318 mayincrease as an increasing function of the distance from the gas inlet306. In some embodiments, the volume of each counterbore 318 may be afunction of one or more of the plenum slope (e.g., the slope of thebottom of the recess 312) or the distance of the counterbore 318relative to the gas inlet 306.

In some embodiments, the counterbores 318 and/or gas outlets 304 may bearranged into zones having one or more counterbores 318 and/or gasoutlets 304 per zone. Each zone, such as zone 312 and zone 314 shown inFIG. 3A, includes one or more counterbores 318 and/or gas outlets 304having the same volume. The volumes of the counterbores 318 and/or gasoutlets 304 that comprise each zone may vary between other zones. Insome embodiments, the volumes of the counterbores 318 and/or gas outlets304 in each zone may increase between adjacent zones as a function ofthe distance of the zone from the gas inlet 306, thereby facilitatingincreased gas flow in zones more distant from the gas inlet 306. Thezones may be similar or dissimilar in size. In some embodiments, threezones may be provided.

In some embodiments, combinations of the above features may be provided.For example, in some embodiments, a slit valve may be provided having asloped plenum 310 whose volume increases in a direction moving away fromthe gas inlet 306. Up to about 96 gas outlets 304 may be provided, eachhaving a counterbore 318. The gas outlets 304 may be substantiallyequidistantly spaced from each other. The gas outlets 304 may bearranged into three different zones. The diameter of the gas outlets 304may increase from zone-to-zone in a direction moving away from the gasinlet 306. In any of the above embodiments, the flow rate of gas exitingeach gas outlet 304 may be controlled to be uniform to greater thanabout 70 percent, or in some embodiments, greater than about 80 percent,or in some embodiments, greater than about 90 percent, or in someembodiments, between about 90 to about 97 percent.

Thus, methods and apparatus suitable for facilitating more uniformdelivery of a gas or gases have been provided herein. The improveduniformity may be at least greater than about 70 percent, and, in someembodiments, up to about 97 percent. The slit valves may be configuredin a two plenum arrangement wherein a gas flow may be equalizedutilizing the two plenums. Alternatively, the slit valves may beconfigured having one plenum and a plurality of flow control featureswherein the gas flow may be equalized by at least one of varying thecross section of the plenum along a longitudinal length, providingcounterbores in the gas outlets, varying the cross sectional area of thecounterbores and/or the gas outlets along a longitudinal length of theplenum, or combinations thereof.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A slit valve, comprising: a housing having an opening disposedtherethrough, the opening configured to allow a substrate to passtherethrough; a gas inlet formed in the housing; an outer plenumdisposed in the housing and coupled to the gas inlet; an inner plenumdisposed in the housing and coupled to the outer plenum via a pluralityof holes; and a plurality of gas outlets disposed in the housing andfluidly coupling the opening to the inner plenum.
 2. The slit valve ofclaim 1, wherein the outer plenum circumscribes the inner plenum.
 3. Theslit valve of claim 1, wherein the plurality of holes are substantiallyequidistantly distributed about a sidewall of the inner plenum
 4. Theslit valve of claim 1, wherein the plurality of holes are offset fromthe plurality of gas outlets.
 5. The slit valve of claim 1, wherein theplurality of gas outlets comprises about 20 gas outlets.
 6. A slitvalve, comprising: a housing having an opening disposed therethrough,the opening configured to allow a substrate to pass therethrough; a gasinlet formed in the housing; a plenum disposed in the housing andcoupled to the gas inlet; a plurality of gas outlets disposed in thehousing and fluidly coupling the opening to the plenum; and acounterbore disposed on a plenum side of one or more of the gas outlets.7. The slit valve of claim 1, wherein a counterbore is disposed on aplenum side of each of the gas outlets.
 8. The slit valve of claim 7,wherein the plenum has a volume that varies along a longitudinal lengthof the plenum.
 9. The slit valve of claim 8, wherein the volume of theplenum increases in a direction moving away from the gas inlet.
 10. Theslit valve of claim 8, wherein the plurality of gas outlets furthercomprise a plurality of zones, each zone comprising one or more gasoutlets having a volume that is different than a volume of gas outletsdisposed in at least one other zone.
 11. The slit valve of claim 1,wherein the plenum has a volume that varies along a longitudinal lengthof the plenum.
 12. The slit valve of claim 11, wherein the volume of theplenum increases in a direction moving away from the gas inlet.
 13. Theslit valve of claim 6, wherein the plurality of gas outlets furthercomprise a plurality of zones, each zone comprising one or more gasoutlets having a volume that is different than a volume of gas outletsdisposed in at least one other zone.
 14. The slit valve of claim 6,wherein at least one gas outlet has a volume that is different than avolume of at least one other gas outlet.
 15. The slit valve of claim 6,wherein at least one counterbore has a volume that is different than avolume of at least one other counterbore.
 16. The slit valve of claim 6,wherein the plurality of gas outlets comprises up to about 96 gasoutlets.
 17. An apparatus for processing a substrate, comprising: aprocess chamber; and a slit valve coupled to the process chamber, theslit valve comprising: a housing having an opening disposedtherethrough, the opening configured to allow a substrate to passtherethrough; a gas inlet formed in the housing; an outer plenumdisposed in the housing and coupled to the gas inlet; an inner plenumdisposed in the housing and coupled to the outer plenum via a pluralityof holes; and a plurality of gas outlets disposed in the housing andfluidly coupling the opening to the inner plenum.
 18. The slit valve ofclaim 17, wherein the outer plenum circumscribes the inner plenum. 19.The slit valve of claim 1, wherein the plurality of holes aresubstantially equidistantly distributed about a sidewall of the innerplenum
 20. The slit valve of claim 1, wherein the plurality of holes areoffset from the plurality of gas outlets.
 21. An apparatus forprocessing a substrate, comprising: a process chamber; and a slit valvecoupled to the process chamber, the slit valve comprising: a housinghaving an opening disposed therethrough, the opening configured to allowa substrate to pass therethrough; a gas inlet formed in the housing; aplenum disposed in the housing and coupled to the gas inlet; a pluralityof gas outlets disposed in the housing and fluidly coupling the openingto the plenum; and a counterbore disposed on a plenum side of one ormore of the gas outlets.
 22. The slit valve of claim 21, wherein theplenum has a volume that varies along a longitudinal length of theplenum.
 23. The slit valve of claim 21, wherein the plurality of gasoutlets further comprise a plurality of zones, each zone comprising oneor more gas outlets having a volume that is different than a volume ofgas outlets disposed in at least one other zone.
 24. The slit valve ofclaim 21, wherein at least one gas outlet has a volume that is differentthan a volume of at least one other gas outlet.
 25. The slit valve ofclaim 21, wherein at least one counterbore has a volume that isdifferent than a volume of at least one other counterbore.